1. Field of the Invention
The present invention generally relates to an information recording and reproducing apparatus, a disc apparatus and a defect area replacement method, and more particularly to an information recording and reproducing apparatus, such as a hard disk apparatus, a magneto optical disc apparatus, a CD-RW (Compact Disc-Rewritable) disc apparatus, a DVD+RW (Digital Versatile Disc+ReWritable) disc apparatus, DVD-RW (Digital Versatile Disc-ReWritable) disc apparatus and a DVD-RAM (Digital Versatile Disc-Random Access Memory) disc apparatus, that can record and reproduce information in an information recording medium such as a hard disk, a magneto optical disc, a CD-RW disc, a DVD+RW disc, a DVD-RW disc and a DVD-RAM disc, respectively.
2. Description of the Related Art
Currently, a format commonly available for CD-RW discs is being standardized. The standardized format is called “CD-MRW (Compact Disc-Mount Rainier ReWritable)”. In CD-MRW, a CD-RW disc is divided into a plurality of recording areas, which are referred to as“packets”, and a spare area is provided to each recording area. In each recording area, an area where information (user data) are written is referred to as a“data area (DA)”, and an area where a data area is replaced is referred to as a“spare area (SA)”. In general, a data area is formed of 138 packets, and a spare area is formed of 8 packets.
If some trouble is detected for a data area, for example, if the address thereof or data therein cannot be read due to flaws, stains, fingerprints and the like, a spare area is used as a replacement destination area for recording the data again. Such a problematic data area is referred to as a “defect area”. Data are always written per packet in a data area and a spare area. Accordingly, if an error is detected for a data area, it is possible to read and write user data at a high speed by replacing of the defect area per packet. In conventional information recording and reproducing apparatuses, if an error occurs in a packet, the packet is written immediately after the error detection, as disclosed in Japanese Laid-Open Patent Application 11-501760.
In conventional information recording and reproducing apparatuses, however, even if an insignificant defect is detected in a packet, an area corresponding to the whole packet is used, resulting in wasteful use of capacity of the information recording medium. In general, one packet in a CD-MRW disc is composed of 32 small areas (blocks). As a result, when the whole packet is replaced for such an insignificant defect (for example, even if the defect is limited within one block), it is necessary to use spare areas corresponding to 32 blocks. Thus, available spare areas are exhausted instantly.
If a defect area is replaced per block rather than packet, a spare area would be saved. For replacing per block, however, it is necessary to accurately detect a defect per block. If the defect detection accuracy is insufficient, a data portion that could be read at defect detection time cannot be read after the replacement operation.